As consumers become more concerned with energy usage, interest in devices for monitoring the energy consumption of home appliances has grown. Manufacturers have made available power strips and power outlet devices that plug in to power outlets and allow a user to read various energy consumption parameters of an appliance that draws power from the power outlet. However, available energy consumption monitoring devices can be improved upon.
First, while home power monitors are typically employed in an effort to reduce power consumption, such devices initially add to power consumption because they must, themselves, draw power. Typically, the impedance of a current sensor employed by a power monitoring device causes undesired power dissipation, with larger impedances resulting in larger dissipation. Smaller impedances reduce power dissipation, but present accuracy problems in measuring the voltage and current on a noisy AC line. It is therefore desired reduce the power consumption of a power monitoring device while maintaining accuracy of voltage and current measurements.
A second concern with home power monitors is cost. A user is typically motivated to monitor power usage in order to save on energy expenditures. The high cost of power monitoring devices vitiates some of those savings. An objective is therefore to reduce the cost of a power monitoring device by using techniques to eliminate the need for some expensive components.
A third concern with home power monitors is compatibility with a given power distribution system. Home power monitors typically are able to measure power parameters of an appliance connected to either a 50 Hz or a 60 Hz alternating current. A power monitor is desired that adjusts to the current and voltage of the electrical current, thereby allowing a manufacturer to produce a home power monitor that works in any part of the world.